CVE-2011-1576 kernel: net: Fix memory leak/corruption on VLAN GRO_DROP

[Petr Matousek <pmatouse () redhat com>]

The function napi_reuse_skb is only meant to be used for packets merged
by GRO. Using it on the VLAN path will lead to memory leaks/corruption.

The fix for CVE-2011-1478 unveiled this issue. Note, this is not a
CVE-2011-1478 regression.

This issue does not affect the upstream kernel as the code path in
question is no longer reachable due to changes in the VLAN subsystem.

https://bugzilla.redhat.com/CVE-2011-1576

Thanks,
-- 
Petr Matousek / Red Hat Security Response Team